Mode-locked operation of a Nd:YLF laser and amplification in aQ-switched Nd:glass slab laser

A Nd:YLF laser pumped with a CW dye laser and acoustooptically mode locked at 38 MHz has an output power of 130 mW and a pulse length of 60 ps. Insertion of intracavity etalons and misaligning the mode locker allows for stable operation with a continuous range of pulse lengths from 60 ps to 4 ns. The 1.053-μm emission permits amplification of these pulses in a Q-switched Nd:phosphate glass slab laser oscillator up to intensities limited by optical damage     

Simultaneous determination of the spectral and temporal properties of tunable, single, picosecond pulses from a short cavity dye laser

We report simultaneous quantitative spectral and temporal measurements of the output pulses from a single-axial mode rhodamine 6G short cavity (1-8 mum) dye laser. The dye laser was pumped at 10 Hz with single second harmonic (532 nm) pulses from a mode-locked Nd⁺³:YAG laser. Spectral measurements made with a high resolution spectrograph and temporal measurements made with an ultrafast streak camera indicate the production of Fourier transform limited pulses for near threshold operation. Output pulses of 7-14 ps (FWHM) are observed from the short cavity dye laser when pumped with 15-30 ps duration 532 nm pulses. The output pulse delay and jitter are also investigated. A theoretical model for the temporal evolution of the pulses is presented and compared with the experimental results.     

Synchronous amplification of subpicosecond pulses

In high-gain dye amplifiers, the effective storage time of the gain medium is only a few hundred picoseconds. Therefore, efficient amplification of ultrashort pulses places a stringent requirement on the synchronization between the pump pulse and the pulse to be amplified. We present a technique of short pulse generation using a dye laser synchronously pumped by a frequency-doubled CW mode locked Nd:YAG laser. Pulses as short as 70 fs are produced. The short optical pulses are subsequently amplified with two different synchronous amplification schemes using 100 ps pulses to establish the gain in the dye amplifier stages. Subpicosecond pulses with energies from a few hundred nanojoules at 500 Hz to a few hundred microjoules at 7 Hz can be obtained.     

波长可调的ps超短腔染料激光器的研究

本文报道了用锁模磷酸盐玻璃激光的倍频光泵浦若丹明B超短腔染料激光器的实验装置和实验结果,用TPF和OSA的组合装置研究了磷酸盐玻璃激光器的最佳运转条件,得到了脉宽～5ps的锁模脉冲系列,以此ps光源泵浦的染料激光器获得了波长为620.1～641.6nm,脉冲宽度小于4ps的单模可调谐激光输出。     

主动锁模和调Q Nd:YAG激光倍频同步泵浦染料激光器特性研究

本文介绍一种主动锁模和调Q Nd:YAG激光倍频同步泵浦可调谐染料激光器。由此激光器已获得脉冲宽度为70ps,脉冲能量为0.1μJ,调Q重复率达7kHz,调谐范围为580～610nm的微微秒脉冲,本文还研究了这一激光器的时间和频谱特性,分析了腔长失配对脉宽和中心波长的影响。     

Two frequency self-injected flashlamp pumped dye laser for nonlinear optics experiments

A high-power short pulse (self-injected) version of a two frequency flashlamp pumped dye laser is presented. Stable nanosecond duration pulses are obtained with a gain in output intensity of a factor of 12 with respect to the normal (long pulse) dye laser configuration over the tuning range of Rhodamine6G. The first results of non-linear excitation of surface polaritons in solids with this source are reported.     

Dual frequency subnanosecond pulses from a millimeter-cavity dye laser

Dual frequency dye laser pulses of subnanosecond duration can be achieved by taking advantage of the spiking behavior of two lasing dyes within a single high-loss cavity. Two 10-kW pulses 1.5 ns apart were observed, each of 600-ps width, at wavelengths of 565 and 615 nm, respectively. The phenomenon of spiking in organic dye lasers has received attention as a potential mechanism for the creation of useable short pulses [1]-[4]. The feasibility of this was recently demonstrated by Lin and Shank [5], who achieved subnanosecond pulses from a nitrogen laser pumped dye laser with a high-loss cavity. By maintaining proper control of the pumping level and the cavity loss, they were able to isolate the initial dye laser spike which occurs with each pump pulse, while suppressing the formation of the relaxation oscillations which usually follow it.     

Efficient generation of picosecond pulses at 243 nm

A new method is reported for generating tunable picosecond light pulses in the ultraviolet region of the spectrum. The system consists of a synchronously pumped mode-locked coumarin 102 dye laser which is mode-matched into an enhancement ring cavity with a mode spacing tuned to the repetition rate of the dye laser. A frequency modulation locking technique locks the carrier frequency of the mode-locked dye laser pulse train to the enhancement cavity. A beta-barium borate crystal was used to produce an average power of greater than 70 mW at 243 nm. There are many potential applications for this source, including the investigation of the 1S to 2S transition in atomic hydrogen using Doppler-free two-photon coherent multiple pulse spectroscopy     

氟化氪准分子激光在氢气中受激拉曼散射阈值的实验研究

对纳秒级准分子激光泵浦的拉曼种子源的阈值特性进行了实验研究,讨论了受激拉曼散射过程的阈值条件及定义.实验测量了脉宽为25ns的氟化氪准分子激光在不同聚焦参数和不同氢气气压下的受激拉曼散射阈值.最后,分析了聚焦参数及四波混频过程对泵浦阈值的影响.     

High-repetition tunable picosecond dye laser pumped by a copperbromide laser

It is reported that by mixing the saturable absorber DODCI with the gain medium Rh6G, 30-ps pulses can be generated from a short-cavity dye laser pumped by a copper bromide laser with a 25-ns pulsewidth and a 10-kHz repetition rate. A theoretical analysis of pulse shortening by this method is shown to agree with experimental results. A dispersion-amplifier system was employed for synchronous amplification and frequency tuning of the dye laser. The single-pulse energy was up to 0.15 μJ with a linewidth-of 1.0 cm^-1 in a one-stage amplifier, and the amplified spontaneous emission (ASE) background noise was reduced to below 10%. By simply rotating the grating and occasionally adjusting the thickness of the dye cavity slightly, the laser can be tuned continuously from 570 to 590 nm with a nearly Fourier-transform-limited linewidth. The repetition rate can be varied from 10 to 20 kHz     

Narrow-band infrared picosecond pulses tunable between 1.2 and 1.4 µm generated by a traveling-wave dye laser

A novel type of picosecond light source is the traveling-wave dye laser. It consists of a generator and an amplifier cell, both pumped by single pulses. Using the fast switching dye No. 5 with a fluorescence quantum efficiency of5 times 10^{-4}, one obtains an energy conversion of the pump to the IR pulse of up to 10 percent. The spectral width of the IR pulses is 15 cm^-1over the tunability range of1.18-1.4 mum. At 1.33 μm we observe Gaussian shaped pulses of 4.4 ps duration for pump pulses of 4.5 ps generated by a mode-locked Nd:glass laser. The output pulses show a high stability with a jitter of less than 0.2 ps.     

Temporal and spectral studies of a synchronously pumped dye laser: Detailed interpretation of autocorrelation measurements

With the combination of precise autocorrelation and spectral measurements we have established the influence of pulse substructure on the determination of pulse envelope duration of a synchronously pumped dye laser within the noise burst model of Pike and Hersher. Our results make a single sided exponential pulse shape unlikely and we present evidence supporting pulses having Gaussian or skewed Gaussian temporal profiles.     

Energy scaling and beam quality studies of a zigzag solid-stateplastic dye laser

Studies of the energy scaling and beam quality improvement of a long-pulse laser pumped solid-state dye laser using a unique new zigzag optical configuration are presented. A beam quality of 1.7 XDL was measured using an unstable optical cavity at a laser output of 200 mJ. Single pulse energies as high as 1 J have been achieved. The laser has been operated at 5 Hz with an average output of about 250 mJ for runs up to 200 pulses     

激光等离子体诊断用微微秒紫外高功率激光脉冲的产生

氙灯泵浦的可调谐染料激光器锁模脉冲用XeCl准分子激光器泵浦的三级染料激光放大器放大后,经倍频再用XeCl准分子激光器放大,在308毫微米处获得了微微秒高功率激光脉冲输出,其峰值功率可达500兆瓦,功率净增益为200。     

On the design of multipass dye laser amplifiers

We describe a universal method for designing multipass dye laser amplifiers typically pumped longitudinally by Q-switching high-energy pulses. The method is based on a set of normalized curves for the gain and on the experimental measurement of the amplifier noise. In this way, the method tries to maximize the gain and to reduce or control the losses in terms, of amplified spontaneous emission and reabsorption of the signal by the uninverted amplifying material. It has been tested to design and optimize a high-gain multipass amplifier for picosecond pulses. The realized system has a compact geometry and offers a gain of over 36 dB, with output pulse energy of 14 μJ and few megawatts of peak power     

Characteristics of organic dye lasers as tunable frequency sources for nanosecond absorption spectroscopy

The properties of 1, 1' diethyl-γ-cyano-2,2'-di-carbocyanine-tetrafluoroborate (DTCDCT)and 1, 1'-diethyl-γ-nitro- 4, 4'-di-carbocyanine-tetrafluoroborate (DTNDCT) lasers have been investigated. High-efficiency (25 percent) spectral narrowing of the normal 150-Å-wide, 2-MW output of DTCDCT (around λ 7600 Å) to <0.01 Å, corresponding to a single longitudinal mode, is achieved with a novel longitudinally pumped (by giant pulse ruby laser) dye laser cavity. Beam divergence is <0.5 mrad, and spectral tunability is obtained by rotating the echelle grating and Fabry-Perot etalon cavity elements. DTNDCT transversely pumped by a mode-locked ruby laser (>150 MW peak power) produces a train of 100 percent modulated mode-locked dye laser pulses whose risetimes (<0.5 ns) and pulse widths (0.6 ns) are detector limited. The production of broad continua for nanosecond absorption spectroscopy is also described, together with measurements on the synchronization of the pumping and dye laser pulses. Finally, the direct spectrographic detection of near-resonant optical-frequency Stark effects in potassium is briefly described. Employing the DTCDCT continuum as absorption source, a red shift of75 times 10^{-3}cm^-1of the λ 7699-Å resonance line was detected for a ruby laser perturbing field of power density ∼ 30 MW/cm^-2.     

Temporal resolution of an AlxGa1?xAs/GaAs bias-free photodetector

We report on the measurement of the temporal resolution limit of a recently reported AlxGa1?xAs/GaAs bias-free photodetector. When tested by dual synchronously pumped dye laser pulses with a repetition rate of 80 MHz and an attenuated energy per pulse of 30 pJ, the detector shows a resolution limit of ? 65 ps.     

Single-frequency operation of a long-pulse e-beam excited XeF(C-A)laser

A 1-m gain length e-beam excited XeF(C-A) excimer laser operating in a unique reimaging ring amplifier configuration has been used to amplify an ultranarrowband single-mode dye laser pulse. Double heterodyne detection was used to simultaneously determine the single-mode injection dye laser and the amplified XeF(C-A) laser bandwidths. Fast Fourier transform (FFT) analysis of the pulses indicates that the amplifier output has the same bandwidth as the injected dye laser pulse. The bandwidth of the XeF(C-A) laser was line narrowed by 6 orders of magnitude, from a free running value of 16 nm (20000 GHz) to 20 MHz. Specific output energies of 0.7 J/l at 488 nm and 1.3 J/l at 476.5 nm were measured. Laser output pulse lengths up to 500 ns were observed     

Generation and kilohertz rate amplification of synchronizedfemtosecond and picosecond laser pulses

Synchronized femtosecond and tunable picosecond laser pulses have been generated using a linear cavity configuration in both lasers. The long-term stability of the synchronization, as well as the frequency of the synchronously pumped femtosecond dye laser, is assured by active stabilization of the cavity length. Additionally, the picosecond and femtosecond pulses have been amplified in dual amplifier chains to pulse energies in the microjoule range at a 1 kHz repetition rate. The total peak intensity available for two-photon, nonlinear excitations is on the order of 10⁹ times greater than that available from unamplified beams     

Characterization of an ultrahigh peak powerXeF(C→A) excimer laser system

The gain characteristics of an electron-beam pumped XeF(C→A) excimer amplifier operating in the blue-green spectral region were investigated for several laser pulse lengths. Saturation energy densities of 50 and 80 mJ/cm² were measured for injected laser pulse durations of 250 fs and ~100 ps, respectively. A gain bandwidth of 60 nm was observed with ~100-ps pulse injection. Using an optimized unstable resonator design, the laser amplifier has produced 275-mJ pulses with a pulse duration of 250 fs and a 2.5 times diffraction-limited beam quality, making the XeF(C→A) amplifier the first compact laser system in the visible spectral region to reach peak powers at the terawatt level